textproduct: Rapid City

KEY MESSAGES

- Warmer temperatures continue this week, with highs mainly in the 80s

- Chances of showers and thunderstorms will increase Tuesday night and continue through the rest of the week

DISCUSSION

(This Evening Through Monday) Issued at 1203 PM MDT Mon May 25 2026

Current upper-air analysis and water vapor imagery depict large- scale ridging over the Rockies and troughing along the PAC NW coast. A surface low remains positioned just off the coast. WV imagery indicates increased moisture over south-central SD, where isolated thunderstorms are possible this afternoon and evening, though conditions are more favorable farther east. Radar currently shows a few weak returns associated with possible developing convection over the northern Black Hills. Surface observations show temperatures mainly in the 80s with light and variable winds across the region.

As the trough propagates eastward, increased southerly/southeasterly low-level flow will bring higher dewpoints into the area this afternoon and evening, especially across south-central SD. HREF guidance shows dewpoints rising into the 50s and lower 60s along with 0-6km bulk wind shear values of 25-35kts. Current CAM guidance continues to favor convective initiation over north-central NE before storms move into southeastern SD. However, an isolated thunderstorm or two can't be ruled out for south-central SD. Similar to the last couple of days, pop-up showers and an isolated thunderstorm or two may develop over and around the Black Hills through the afternoon and into the evening hours. High temperatures will range from the 80s to lower 90s today and persist through the week under continued ridging across the region.

By Tuesday afternoon, ensemble guidance shows the trough evolving into a cut-off low over OR/northern CA. This pattern will support a more active and unsettled weather regime across the region with near- daily thunderstorm chances through much of the week. Current SPC outlooks maintain general thunderstorms through Wednesday with no organized severe weather expected. This more active pattern is expected to continue through the weekend and into next week.

AVIATION

(For the 18Z TAFS Through 18Z Tuesday) Issued At 1109 AM MDT Mon May 25 2026

VFR conditions are expected through the forecast period. Isolated showers or thunderstorms may develop in/near Black Hills, but confidence in the storms reaching KRAP is very low. Increasing southerly winds expected near the end of the forecast period (after 26/12-14z).

FIRE WEATHER

Issued At 1203 PM MDT Mon May 25 2026

Even withgreen-up occurring across the region, relative humidity values over the next couple of days will fall into the mid-teens to low-20s across much of the area south of I-90. In addition to low RH values, gusty southerly/southeasterly winds are expected to develop Tuesday morning, leading to elevated fire weather conditions south of I-90.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.